Drop formation behaviour of a hydrate-forming liquid in a water stream

Experiments were carried out to investigate the drop formation behaviour of a hydrophobic hydrate-forming liquid, HCFC-141b (CH3CCl2F), at a single nozzle in a water stream under hydrate-formable thermodynamic conditions. Attention was focused on the relation between the clathrate-hydrate formation and the drop formation. It was observed that two discrete hydrate crusts grow along the liquid-liquid interface; one forms a frontal cap and the other forms a cylindrical root on each growing drop before its detachment from the nozzle. Most of the latter crust remains at the tip of the nozzle after the detachment of the drop so that it grows into a bell-shaped or nearly cylindrical funnel composed of hydrate deposits in the course of successive growth/detachment of drops. The size of these drops is dependent on the instantaneous diameter of the hydrate-funnel tip rather than the diameter of the nozzle itself. Thus, the size of the drops successively released into the water stream generally varies synchronously with quasi-periodical alternation of growth and breaking of the hydrate funnels. The growth and breaking of the hydrate funnels and the resultant drop-size variation are significantly dependent on the system temperature (or the system subcooling from the liquid/liquid/hydrate equilibrium temperature), the nozzle diameter, and the velocity of the drop-forming liquid through the nozzle.